Alright, let's solve this math problem step by step. First, we have the number 841. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 20. So, we're going to take the number 841 and add it to itself 20 times.
Step 1: 0 + 841 = 841
Step 2: 841 + 841 = 1682
Step 3: 1682 + 841 = 2523
Step 4: 2523 + 841 = 3364
Step 5: 3364 + 841 = 4205
Step 6: 4205 + 841 = 5046
Step 7: 5046 + 841 = 5887
Step 8: 5887 + 841 = 6728
Step 9: 6728 + 841 = 7569
Step 10: 7569 + 841 = 8410
Step 11: 8410 + 841 = 9251
Step 12: 9251 + 841 = 10092
Step 13: 10092 + 841 = 10933
Step 14: 10933 + 841 = 11774
Step 15: 11774 + 841 = 12615
Step 16: 12615 + 841 = 13456
Step 17: 13456 + 841 = 14297
Step 18: 14297 + 841 = 15138
Step 19: 15138 + 841 = 15979
Step 20: 15979 + 841 = 16820

So, 841*20 = 16820